Confused about length of treatment

I'm ordering a zapper and was a bit confused about the length of time needed to treat the parasites.

When I read Dr. Clark's info on zapping it sounded like the three 7 minute treatments with a 20 minute break each was sufficient to kill all of the offending creatures in the system. Is that correct? If not, and we have to keep repeating the process, then what is being killed during one full treatment, and why do we get new growth so quickly?

"But it takes more than one treatment. It takes three treatments to kill everything. Why? The first zapping kills viruses, bacteria and parasites. But a few minutes later, bacteria and viruses (different ones) often recur. I conclude they had been infecting the parasites, and killing the parasites released them. The second zapping kills the released viruses and bacteria, but soon a few viruses appear again. They must have been infecting some of the last bacteria. After a third zapping I never find any viruses, bacteria or parasites, even hours later. (From: " The Cure For All Diseases ", p. 13ff.; copyright notice)